[draegtun]

> I've always wanted to work with a language that supports contracts (originally Eiffel I guess). Would love to see this hacked into Go.

There have been a few attempts to hack (design by) contracts into Perl. Here are some which can be found on CPAN:

* Class::Agreement - https://metacpan.org/module/Class::Agreement

* Class::Contract - https://metacpan.org/module/Class::Contract

* Sub::Contract - https://metacpan.org/module/Sub::Contract

Sub::Contract is my favourite because it's lightweight, pragmatic & with a more Perlish implementation.